Organized thematically, the 90 works immerse viewers in sunlight and shadow as it plays on subjects such as Europe's formal gardens, watery scenes from Venice, friends lounging in meadows, characters at Bedouin camps and the marble quarries of Carrara, Italy. A few companion oil paintings show how effortlessly Sargent moved between mediums, sometimes rendering the same scene in both.

Museum of Fine Arts, Houston director Gary Tinterow suggested a new way to view Sargent. "He's one of the greatest watercolorists who has ever lived," Tinterow said. "With this medium, there's no room for mistakes because every mark shows on the paper."

Sargent called the watercolorist's task "making the best of an emergency."

Tinterow has noticed museum visitors spending more time with these paintings than they typically do in an exhibition. "Something about them invites introspection. You can see the artist making decisions," he said.

While Sargent's technical brilliance shows with virtually every brush stroke, and he began to use wax during this period - from 1902 to 1911 - his use of white space and subtle pastel shades is especially intriguing. White highlights may be the last thing an artist adds to an oil painting, but they're the first consideration with watercolor; areas of the paper are often left blank.

Sargent didn't so much paint the sculptural fountain of "In a Medici Villa," for example; he painted the shadows that define it. The voluminous white skirts of the women in "Simplon Pass: Reading," the sheets hanging out to dry in "La Biancheria" and the leafy trees in "Corfu: Lights and Shadows" also cast a sunny spell.

In situations he could control, Sargent still meticulously posed figures, using white umbrellas to diffuse the sunlight. That wasn't the case when he visited the Ottoman Levant, a region that now includes Israel, Jordan and Syria. (Sargent went there in 1905 and 1906 to research themes for the Boston Public Library mural commission that helped him become financially independent.) The two intense figures in "Bedouins" look captured on the fly, peering through the hoods of their blue thobes. You can also sense the harshness of the desert light.

Sargent wasn't after postcard-perfect scenery. Aside from the play between sunlight and shade, he evoked a freewheeling dynamic with odd angles and tight cropping. He didn't include the top of that fountain in "In a Medici Villa." Nor did he express the symmetry of formal gardens. He painted the Santa Maria Della Salute basilica more than any other motif in Venice but never showed the entire building. "They're like film close-ups. It's a very modern way of looking at the world, where you have to look at more than one image to see the whole thing," Hirschler said.

Venice was one of Sargent's favorite places to paint, she added. "What better place to paint with watercolor? The whole place seems like it might just dissolve in front of you, and he does a great job of capturing that."

Pencil sketches can't be hidden with watercolor, and she noted how Sargent used them to draw only the building in "Santa Maria Della Salute," painting the foreground's boats and figures more freely to evoke the difference between the environment's solid and floating elements.

The figures in Sargent's watercolors represent a departure, too. "It's a wonderful experimental moment; he's figuring out how to paint people without doing portraits," Hirschler said. Often they appear oblivious to him, almost a part of the landscape - "what I would call an anti-portrait," Hirschler added. Yet he also manages to capture expressions vividly, even without under-drawing.

A different modernism

Sargent's watercolors show pure delight in painting that was not intended for an audience.

Born in Florence, Italy, to American parents, Sargent went to art school in Paris and eventually settled in London, a consummate international traveler. He painted with watercolors even as a teenager and carried them wherever he traveled as an adult, but he always held the paintings close. His family found hundreds of them in his studio when he died in 1925 at age 69.

Sargent's friends could acquire a watercolor two ways during the artist's lifetime, Hirschler said: "You could get married and get one as a gift, or you could fall out of his gondola in Venice, and he'd give you one as compensation."

The two large collections that comprise "John Singer Sargent: The Watercolors" have been framed cohesively and mixed together for the show, so you might not know without reading the labels where they're from. They're owned by the Brooklyn Museum and the Museum of Fine Arts, Boston, which bought them - in their entireties - in 1909 and 1912, respectively.

For years, art historians have characterized Sargent as a savvy self-promoter. He helped several East Coast museums build their first collections. But in researching letters between Sargent and the Bostonian Edward "Ned" Darley Boit, Hirschler and Carbone found surprises.

It was Boit, not Sargent, who in 1908 pushed for the artist's first showing of watercolors in America. They'd been friends since 1882, when Boit commissioned one of Sargent's best-known portraits, "The Daughters of Edward Darley Boit."

Sargent insisted the watercolors were not for sale, finally relenting that he didn't want to sell them piecemeal. "If by any chance some Eastern Museum, or some Eastern collector wanted to buy the whole lot en bloc, I might consider it," he wrote. No matter that some of the first group contained just a few wet strokes, pulled from Sargent's studio; the Brooklyn Museum snapped them up. Sargent created the second show more purposefully, and the Boston museum bought it even before it was hung.

Until "John Singer Sargent: The Watercolors" debuted last year, the collections hadn't been shown side by side. (Given their delicacy, they're not likely to come out of storage for a long time again.) The show's timing in Houston, with "The Age of Impressionism" on view a few more weeks and "Georges Braque: A Retrospective" nearly concurrent, offers additional perspective.

Some of Sargent's earlier works show the influence of his friend, the great Impressionist Claude Monet. Then he veers toward more modern abstraction with paintings made at Carrera in 1911.

"The history of 20th-century art has been written in such a way that we think there was only one track - Pablo Picasso," Hirschler said. "But there were lots of things going on at the same time." In 1909, Picasso was just one of many experimental artists showing in some little gallery in Paris. Sargent, part of the artistic establishment, had a serious public-relations problem with critics who advanced the cause of modernism.

Today scholars are reconsidering the entire scene, Hirschler said. Sargent wasn't the only artist clinging to beauty and subjects: Figurative art also flourished in works by Frederick Remington, Grant Wood and John Steuart Curry.

"A century later, that's kind of a lesson," Hirschler added. "What's going to be exciting is re-writing the 20th-century art story."

However and whenever it happens, Sargent should be at the head of the class.